This invention relates to a child safety seat for use in a vehicle.
It is well known for a child safety seat to rest on a vehicle seat and to be secured thereon by the corresponding vehicle seat belt. The disadvantage of this arrangement is that, even if the vehicle seat belt is pulled very tight during installation, the resilience of the belt, will permit undesirable movement of the child seat relative to the vehicle in the event of sudden deceleration, for example, during an accident. In order to overcome this disadvantage, it has been proposed to provide vehicle seats with standard anchorage units at agreed locations for engagement by releasable connectors which are attached to the child seat structure by rigid links. Such anchorage units will be referred to hereinafter as xe2x80x9cstandard anchorage unitsxe2x80x9d.
The invention relates to a child safety seat of the type comprising a child seat structure having a base support surface for resting on a vehicle seat cushion, a back support surface for abutting against the seat back of said vehicle seat, a rigid link projecting from the child seat structure between the base support surface and the back support surface, and a releasable connector mounted on the rigid link for engagement with a standard anchorage unit associated with the vehicle seat.
U.S. Pat. No. 6,082,819 discloses such a child safety seat for use with two standard anchorage units located near the rear edge of the vehicle seat cushion and the bottom of the vehicle seat back. This arrangement is subject to the disadvantage that, in the event of an accident, the child seat tends to rotate about the standard anchorage units, compressing the front part of the vehicle seat cushion and allowing undesirable forward movement of the head of a child occupant of the child seat. The present invention aims to provide a child safety seat in which this disadvantage is mitigated.
According to the invention, in a child safety seat of the type described above, the rigid link is pivotally attached to the child seat structure.
Preferably the rigid link is pivotally attached to the child seat structure at a pivot location above the base support surface.
In the event of sudden deceleration, operation of this arrangement differs from the prior art in that the centre of gravity of the combination of the child seat structure and the seat occupant does not rotate about the standard anchorage units at a constant radius. Instead both the front and rear edges of the base support surface are pressed downwards into the vehicle seat cushion simultaneously. This results in a reduction in the distance of this centre of gravity from the anchorage units and therefore a corresponding reduction in the rotational moment exerted by the inertia of the child seat. The overall result is a reduction of the extend of forward excursion of the child""s head.
Preferably, each rigid link is L-shaped with a first limb carrying the corresponding connector and a second limb having its free end pivotally attached to the child seat structure. In normal use, the first limb lies in a rearward continuation of the plane of the base support surface and the second limb is generally parallel to the back support surface.
The height of the pivot location above the base surface is at least 30 mm so as to be greater than the reduction of the thickness of the vehicle seat cushion when it is fully compressed.